The present invention relates to investment casting, and more specifically to wax molds for investment casting.
The investment casting process (or lost wax process) has been used for thousands of years to create components out of metal. The process starts by creating a pattern out of wax that is a close replica of the final part. The wax pattern gets attached to a sprue to form a mold. The mold gets dipped or “invested” in liquid ceramic and then coated with sand to develop a ceramic shell around the mold. That dipping process can occur multiple times so that a sturdy shell is created around the wax. The wax is then removed (i.e., melted away), the empty mold is heated, and metal is poured into the empty mold. The cast parts are removed from the ceramic shell and finished to final form.
Wax patterns are created with a “gate” attached to them. The gate is the spot where 1) the wax pattern is attached to the sprue to create the mold; 2) the metal flows into the part; and 3) the parts gets separated from the sprue after the part is poured. Assembly of the mold occurs by attaching the wax patterns to the sprue. Attaching the wax patterns to the sprue typically includes the use of a guide that identifies placement of the patterns on the sprue. The guide is placed next to the sprue and the operator marks, typically with a marker, the spot on the sprue where the pattern is to be attached. Operators then heat a flat distal end of the gate and/or flat mating surface of the sprue, orient and place the gate in the previously marked location, and then melt the wax on the gate and sprue to “weld” the gate/pattern to the sprue. A torch is commonly used by the operator to perform this welding. The process is then repeated with each pattern until the mold is completely assembled.